A5036135416- Biofuel production and bioconversion
- Microbial Metabolic Engineering and Bioproduction
- Plant Gene Expression Analysis
- Chemical Synthesis and Characterization
- Radioactive element chemistry and processing
- Plant-Microbe Interactions and Immunity
- Bioenergy crop production and management
- Plant Parasitism and Resistance
- Mycorrhizal Fungi and Plant Interactions
- Extraction and Separation Processes
- Plant biochemistry and biosynthesis
- Biochemical and biochemical processes
- X-ray Diffraction in Crystallography
- Advanced Cellulose Research Studies
- Enzyme-mediated dye degradation
- CRISPR and Genetic Engineering
- Crystallization and Solubility Studies
- Lignin and Wood Chemistry
- Legume Nitrogen Fixing Symbiosis
- Fungal and yeast genetics research
- Clostridium difficile and Clostridium perfringens research
- Crystallography and molecular interactions
- Photosynthetic Processes and Mechanisms
- Enzyme Catalysis and Immobilization
- Enzyme Structure and Function
Oak Ridge National Laboratory
2016-2025
University of North Texas
2022
National Renewable Energy Laboratory
2020
United States Department of Energy
2019
Oak Ridge Associated Universities
2017-2018
Bioenergy Life Science (United States)
2013-2014
University of Tennessee at Knoxville
2003
Texas Tech University
2003
Virginia Tech
2003
Pacific Northwest National Laboratory
2003
A nanostructured, carbon-based physical catalyst electrochemically reduces N 2 to ammonia under ambient conditions.
Effective enzymatic hydrolysis of lignocellulosic biomass benefits from lignin removal, relocation, and/or modification during hydrothermal pretreatment. Phase transition, depolymerization/repolymerization, and solubility effects may all influence these changes. To better understand how is altered, Populus trichocarpa x P. deltoides wood samples cellulolytic enzyme (CEL) isolated were subjected to batch flowthrough pretreatments. The residual solids liquid hydrolysate characterized by gel...
Abstract Lignin biosynthesis is evolutionarily conserved among higher plants and features a critical 3-hydroxylation reaction involving phenolic esters. However, increasing evidence questions the involvement of single pathway to lignin formation in vascular plants. Here we describe an enzyme catalyzing direct 4-coumarate caffeate as bifunctional peroxidase that oxidizes both ascorbate at comparable rates. A combination biochemical genetic model Brachypodium distachyon Arabidopsis thaliana...
Very few cultivated microorganisms can degrade lignocellulosic biomass without chemical pretreatment. We show here that "Anaerocellum thermophilum" DSM 6725, an anaerobic bacterium grows optimally at 75 degrees C, efficiently utilizes various types of untreated plant biomass, as well crystalline cellulose and xylan. These include hardwoods such poplar, low-lignin grasses napier Bermuda grasses, high-lignin switchgrass. The organism did not utilize only the soluble fraction since insoluble...
Abstract Background Plants have developed defense strategies for phytopathogen and herbivore protection via coordinated metabolic mechanisms. Low-molecular weight metabolites produced within plant tissues, such as salicylic acid, represent one mechanism which likely mediates – microbe interactions above below ground. Salicylic acid is a ubiquitous phytohormone at low levels in most plants, yet are concentrated compounds Populus , acting selective filter rhizosphere microbiomes. We propagated...
Abstract Background Zymomonas mobilis ZM4 (ZM4) produces near theoretical yields of ethanol with high specific productivity and recombinant strains are able to ferment both C-5 C-6 sugars. Z. performs best under anaerobic conditions, but is an aerotolerant organism. However, the genetic physiological basis ZM4's response various stresses understood poorly. Results In this study, transcriptomic metabolomic profiles for aerobic fermentations were elucidated by microarray analysis...
The model bacterium Clostridium cellulolyticum efficiently degrades crystalline cellulose and hemicellulose, using cellulosomes to degrade lignocellulosic biomass. Although it imports ferments both pentose hexose sugars produce a mixture of ethanol, acetate, lactate, H2 CO2, the proportion ethanol is low, which impedes its use in consolidated bioprocessing for biofuels production. Therefore genetic engineering will likely be required improve yield. Plasmid transformation, random mutagenesis...
Summary 3‐ O ‐caffeoylquinic acid, also known as chlorogenic acid ( CGA ), functions an intermediate in lignin biosynthesis the phenylpropanoid pathway. It is widely distributed among numerous plant species and acts antioxidant both plants animals. Using GC‐MS, we discovered consistent extreme variation content across a population of 739 4‐yr‐old Populus trichocarpa accessions. We performed genome‐wide association studies GWAS ) from 917 P. accessions expression‐based quantitative trait loci...
Lignocellulosic biomass is one of the most promising renewable and clean energy resources to reduce greenhouse gas emissions dependence on fossil fuels. However, resistance accessibility sugars embedded in plant cell walls (so-called recalcitrance) a major barrier economically viable cellulosic ethanol production. A recent report from US National Academy Sciences indicated that, "absent technological breakthroughs", it was unlikely that would meet congressionally mandated fuel standard 35...
Adverse growth conditions can lead to decreased plant growth, productivity, and survival, resulting in poor yields or failure of crops biofeedstocks. In some cases, the microbial community associated with plants has been shown alleviate stress increase under suboptimal growing conditions. A systematic understanding how changes these is required understand contribution microbiome water utilization, nutrient uptake, ultimately yield. Using a inoculation strategy, we studied belowground Populus...
Clostridium thermocellum is a model thermophilic organism for the production of biofuels from lignocellulosic substrates. The majority publications studying physiology this use substrate concentrations ≤10 g/L. However, industrially relevant start at 100 g/L carbohydrate, which corresponds to approximately 150 solids. To gain insight into fermentation high concentrations, we studied growth on, and utilization crystalline cellulose varying 50 by C. thermocellum. Using defined medium, batch...
The recalcitrance of natural<italic>Populus</italic>variants was elucidated.
The biological function of the plant-microbiome system is result contributions from host plant and microbiome members. Populus root a diverse community that has high abundance β- γ-Proteobacteria, both classes which include multiple plant-growth promoting representatives. To understand contribution individual members in community, we studied simplified consisting Pseudomonas Burkholderia bacterial strains isolated hosts inoculated on axenic cutting controlled laboratory conditions. Both...
Trees are associated with a broad range of microorganisms colonising the diverse tissues their host. However, early dynamics microbiota assembly from root to shoot axis and how it is linked exudates metabolite contents remain unclear. Here, we characterised fungal bacterial communities altering as well metabolomes in parallel establishment poplar cuttings (Populus tremula x tremuloides clone T89) over 30 days growth. Sterile were planted natural or gamma irradiated soils. Bulk rhizospheric...
Down-regulation of the caffeic acid 3-O-methyltransferase EC 2.1.1.68 (COMT) gene in lignin biosynthetic pathway switchgrass (Panicum virgatum) resulted cell walls transgenic plants releasing more constituent sugars after pretreatment by dilute and treatment with glycosyl hydrolases from an added enzyme preparation Clostridium thermocellum. Fermentation both wild-type milder hot water no washing showed that only inhibited C. Gas chromatography–mass spectrometry (GCMS)-based metabolomics were...
Clostridium thermocellum is a candidate consolidated bioprocessing biocatalyst, which microorganism that expresses enzymes for both cellulose hydrolysis and its fermentation to produce fuels such as lignocellulosic ethanol. However, C. relatively sensitive ethanol compared ethanologenic microorganisms yeast Zymomonas mobilis are used in industrial fermentations but do not possess native hydrolysis.In this study, was grown mid-exponential phase then treated with final concentration of 3.9 g/L...
Long-lived perennial plants, with distinctive habits of inter-annual growth, defense, and physiology, are great economic ecological importance. However, some biological mechanisms resulting from genome duplication functional divergence genes in these systems remain poorly studied. Here, we discovered an association between a poplar (Populus trichocarpa) 5-enolpyruvylshikimate 3-phosphate synthase gene (PtrEPSP) lignin biosynthesis. Functional characterization PtrEPSP revealed that this...
Within boreal and temperate forest ecosystems, the majority of trees shrubs form beneficial relationships with mutualistic ectomycorrhizal (ECM) fungi that support plant health through increased access to nutrients as well aiding in stress pest tolerance. The intimate interaction between fungal hyphae roots results a new symbiotic “organ” called ECM root tip. Little is understood concerning metabolic reprogramming favors formation this hybrid tissue compatible interactions what prevents tips...
Summary Plant laccases are thought to function in the oxidation of monolignols which leads higher order lignin formation. Only a hand‐full plants have been functionally evaluated, and as such little is known about breadth their impact on cell wall chemistry or structure. Here, we describe previously uncharacterized laccase from Populus , encoded by locus Potri.008G064000, whose reduced expression resulted transgenic trees with changes syringyl/guaiacyl ratios well altered sugar release...
The use of woody crops for Quad-level (approx. 1 × 1018 J) energy production will require marginal agricultural lands that experience recurrent periods water stress. Populus species have the capacity to increase dehydration tolerance by lowering osmotic potential via adjustment. aim this study was investigate how inherent genetic a clone respond drought interacts with nature determine degree biochemical response.A greenhouse stress conducted on deltoides 'WV94' and resulting metabolite...
Drought stress negatively impacts microbial activity, but the magnitude of responses is likely dependent on a diversity belowground interactions. Populus trichocarpa individuals and no-plant bulk soils were exposed to extended drought (∼0.03% gravimetric water content [GWC] after 12 days), rewet, 12-day "recovery" period determine effects plant presence in mediating soil microbiome stability stress. Plant metabolomic analyses indicated that exposure increased host investment C N metabolic...
The factors controlling lignin composition remain unclear. Catechyl (C)-lignin is a homopolymer of caffeyl alcohol with unique properties as biomaterial and precursor industrial chemicals. synthesized in the seed coat Cleome hassleriana switches from guaiacyl (G)- to C-lignin at around 12 14 days after pollination (DAP), associated rerouting monolignol pathway. Lack synthesis limits formation before DAP, but coniferyl still highly accumulated DAP. We propose model which, during biosynthesis,...